Test-type for opticians and oculists



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Patented 001. 13, 1891.

E. & L. CLAUDEL. TEST TYPE T011 oPTIoIANs AND 'ooULIsTs THE NGRRISPETERS C0 PNOTO- IYNO WASHINGTON D C UNITED STATESv PATENT OFFICE.

EDVARD CLAUDEL AND LOUIS CLAUDEL, OF NEV ORLEANS, LOUISIANA.

TEST-TYPE FOR OPTICIANS AND OCULISTS.

SPECIFICATION forming part of Letters Patent No. 461,320, dated October13, 1891.

Application filed April 11, 1891.

Vsuch as will enable others skilled in the art to which it appertains tomake and use the same. Y

This invention has relation to improvements in devices employed byOpticians and oculists to test a patients strength of sight; and it hasfor its object to provide a device of cheap and simple constructionadapted to be readily manipulated, whereby test-types or print ofvarious degrees of fineness may be successively brought into alignmentwith an opening and before a patients eyes, and the strength of sightthereby determined.

To the accomplishment ofthe foregoing and other objects, the inventionconsists in the construction, novel combination, and adaptation of partshereinafter described, and particularly pointed out in the claimappended.

In the accompanying drawings, Figure l is a front elevation of ourimproved device. Fig. 2 is a rear elevation of the same. Fig. 3 is ahorizontal transverse sectional view, and Fig. 4 is a front elevation,of the slide bearing the test type or print.

Referring by letter to the said drawings, A indicates the main or faceboard of our im-y proved device, which is preferably of a rectangularform. This face-board A is provided at about the proportional elevationillustrated with a horizontally-disposed rectangular opening a, throughwhich'the respective species of type or print are exhibitedto thepatient, and the said rectangular opening d is preferably provided witha dark or black border, whereby the print is thrown into relief.

Attached to the back of the board A, adjacent to the longitudinal edgesthereof, are longitudinal strips B, which are provided with a shoulderat their attached edge or are set out from the board A, as illustrated,to

serial No. 388,568. (no model.)

afford longitudinal guideways for thetype or print bearing slide C,which is provided on .its rear side at a suitable point with a tab orbutton D, whereby it may be readily adjusted. At the bottom of the boardA a transverse strip E, of a similar construction to the strips B, isprovided, whereby the downward movement of the slide C is limited. Uponthe face or front side of the slide C, which is of a rectangular form,as shown, we provide at intervals blocks of type or print, which arenumbered, respectively, 1, 2, 3, and 4, and are of a size and form tobeexhibited through the rectangular opening a when theyI are brought inalignment therewith.

In the present embodiment of our invention we `have illustrated fourspecies of type or print-viz., pearl, indicated by 1; brevier, indicatedby 2; small pica, indicated-by 3, and great primer, indicated'by 4-andwe have found by experience that this number and series of species iswell adapted to attain the end desired; vbut it is obvious that ifdesired a greater or l'ess number ot' species might be employed.

At a suitable point upon one of the guidestrips B with respect to therectangular opening a, we providean index-markhand upon the rear side ofthe slide C,at suitable points with respect to the several species oftype or print, we provide index-marks 1, 2, 3, and 4, whereby it will beseen that the operator may stand at the back of the test device andbring any desired species of type or print into alignment with theopening d and before the patients vision by simply registering thenumber of such species with the mark b, before described.

By a device of the construction described it will be seen that anexperienced optician or oculist by simply adjusting the slide C in themanner described may readily ascertain the strength or state of apatients eyes.

Having described our invention, what we claim, and desire to secure byLetters Patent, 1s

The device for testing strength of sight, consisting, essentially, ofthe face-board hav- A ing a sight-opening formed therein and guidewaysformed on the back thereof and also having an index-mark on its back ata suit- IOO able point with respect to the sight-opening, in combinationwith a slide adapted to move in the guideways of said face-board andInarkupon the back of the face-board, sub- 1o stantially as and for thepurpose set forth.

In testimony whereof We affix our signatures bearing species of type orprint of different in presence of two Witnesses. degrees of neness uponits face. and indeX- marks upon its back at suitable points with respectto the several species of type on its faee,'the said index-marks on theslide being designed to be registered with the index- EDWARD CLAUDEL.LOUIS CLAUDEL. Witnesses:

A. P. ROUX, PERCY D. PARKS.

